1. You got it! It is "KIT9.PDF".
2. "SPOUSE CASE" is a case of "Family Class", Nothing special, just means you sponsor your spouse but not your parents or children. You got sheets of Kit9.PDF, but how to fill it out depends on case.
3. It does not matter if you don't use registed-mail, I am afraid it will be lost, so I recommend you using registed-mail. :-)